How much does 1kg of whey last?

December 16, 2025 •

4 min read

Based on a standard 30-gram serving, a 1kg tub of whey protein contains approximately 33 servings. Exactly how much does 1kg of whey last depends on your individual consumption frequency, serving size, and personal fitness goals, making its duration variable from just over two weeks to well over a month.

Quick Summary

The duration of a 1kg whey protein supply is determined by factors like serving size and frequency. Average usage for a single scoop per day lasts around one month, while higher consumption for advanced goals decreases the duration significantly.

Key Points

Serving Size is Key: The duration of your 1kg whey protein depends directly on your serving size. Standard 30g servings yield around 33 uses, while smaller or larger scoops will alter this significantly.
Usage Frequency Matters: Consuming whey once daily makes a 1kg tub last approximately one month, whereas twice-daily consumption halves that time to just over two weeks.
Goals Dictate Intake: Muscle gain requires more protein, leading to faster consumption. Weight loss or general wellness often means fewer servings, extending the whey's lifespan.
Calculate Your Needs: To find your exact duration, divide 1000g by your specific daily serving size. This personalized calculation helps you budget and plan effectively.
Store It Properly: Keep your whey protein in a cool, dry place with the lid sealed tightly. This prevents moisture and heat from degrading the powder and ensures it stays fresh until its expiration date.
Whey Complements Your Diet: Supplementing your daily protein intake with whey should not replace a balanced diet. Use it to fill gaps and meet specific fitness goals rather than relying on it exclusively.

How Serving Size and Frequency Impact Your Whey Supply

Several key factors determine how long your 1kg of whey lasts. The most critical variables are your serving size and how often you consume the supplement throughout the day. While many brands suggest a standard 30g scoop, your personal needs for muscle gain, weight loss, or general protein supplementation will dictate your actual usage.

For example, a person aiming for moderate protein intake might take one scoop (30g) per day, resulting in a supply that lasts approximately 33 days. In contrast, someone with more aggressive muscle-building goals might consume two or more scoops daily, which could reduce the 1kg supply to just over two weeks. This calculation is straightforward: divide the total grams in the tub (1000g) by your desired daily serving size. You can use a kitchen scale for the most accurate measurement, as scoops can provide slightly different amounts depending on the powder's density and how compressed it is.

Calculation Examples for a 1kg Tub (1000g)

One 30g scoop per day: $1000g \div 30g = 33.3$ servings. Lasts approximately 33 days.
Two 30g scoops per day: $1000g \div 60g = 16.6$ servings. Lasts approximately 16 days.
One 25g scoop per day: $1000g \div 25g = 40$ servings. Lasts exactly 40 days.
Two 25g scoops per day: $1000g \div 50g = 20$ servings. Lasts exactly 20 days.

Influencing Factors Beyond Basic Usage

Your fitness objectives play a significant role in how quickly you go through a 1kg tub. For those engaged in intense, consistent resistance training, a higher protein intake is often recommended to support muscle repair and growth. This means a greater daily serving and a shorter lifespan for your whey. Conversely, for individuals using whey to supplement an already protein-rich diet or simply for general wellness, a smaller, less frequent dose is sufficient, extending the tub's lifespan.

Another important consideration is your total dietary protein intake. The whey should not be your sole protein source but rather a convenient way to meet daily protein goals. Assess your total protein from whole foods—like meat, dairy, and legumes—to determine if one, two, or even more whey servings are necessary. The time of consumption, such as a post-workout shake versus an anytime snack, also influences usage patterns but doesn't alter the mathematical duration.

Comparison of Whey Usage Based on Goals


Goal	Daily Servings (30g)	Daily Whey Consumption	Duration of 1kg Whey	Purpose	Examples
Weight Loss	1	30g	Approx. 33 days	Increase satiety, preserve lean muscle mass	Single shake, meal supplement
General Wellness	1	30g	Approx. 33 days	Conveniently meet daily protein requirements	Smoothie, recipe addition
Muscle Gain (Moderate)	2	60g	Approx. 16 days	Enhance muscle repair and synthesis after workouts	Post-workout shake, additional snack
Muscle Gain (Intense)	3	90g	Approx. 11 days	Maximize protein intake for rapid muscle growth	Multiple shakes, added to meals

Conclusion

While a rough estimate suggests a 1kg tub of whey lasts about a month, the reality is far more personalized. By calculating your daily intake based on your serving size and fitness goals, you can precisely determine your supply's longevity. Whether you're aiming for weight loss, muscle gain, or general fitness, adjusting your serving frequency will directly impact how quickly you'll need to restock. Monitoring your consumption ensures you get the most out of your investment while aligning with your nutritional strategy.

Proper Storage for Longevity

To maximize the shelf life of your whey protein, proper storage is crucial. Whey protein powder is a dry product, but moisture and heat can degrade its quality over time and even introduce harmful bacteria. Always store your tub in a cool, dry place away from direct sunlight and seal the lid tightly after every use. A kitchen pantry or cupboard is ideal. While a 'best before' date can last up to two years, following these simple storage tips will ensure your powder remains fresh and potent for its intended duration.

Key Factors to Consider

Serving size (e.g., 25g, 30g, or more) is the primary determinant of duration.
Daily intake frequency (once, twice, or more per day) significantly alters how long a 1kg bag lasts.
Intense training for muscle gain typically requires more protein, shortening the product's lifespan.
Weight loss or general health goals usually involve a single daily serving, making the whey last longer.
Body weight, diet, and activity levels all influence your optimal protein requirement.
Proper storage in a cool, dry place is essential to maintain freshness and potency until the best-before date.
Always check the specific serving size recommendation on your whey protein brand's packaging for the most accurate calculation.

Frequently Asked Questions

A standard 1kg tub of whey protein typically contains around 33 servings, based on an average serving size of 30 grams.

Generally, it lasts longer for weight loss goals, as intake may be moderated to curb hunger. For intense muscle gain, a higher daily intake is needed to support recovery, which shortens the duration.

Most whey protein powders are shelf-stable for a long time. It may be safe to use after the 'best before' date, but its nutritional quality might have decreased. Check for any signs of spoilage, like a foul smell or mold, before consumption.

Store whey protein in a cool, dry location away from direct sunlight and humidity. Always ensure the container is tightly sealed after each use to prevent moisture contamination.

Using a small digital kitchen scale is the most accurate method to measure your protein powder. This accounts for variations that can occur with scoop size and powder density.

Individual protein needs, total daily dietary intake from other sources, and your specific type of training and activity level all influence how much whey you consume and, therefore, its duration.

For many beginners starting with one scoop (30g) per day, a 1kg tub will last approximately 33 days, or just over a month. Beginners with higher protein needs will find it lasts less time.